#include <stdio.h>

#define pstr

#ifdef str
char string1[] = "1234";
char string2[] = "1234";
#endif

#ifdef pstr
char *string1 = "1234";
char *string2 = "1234";
#endif

int main()
{
    if (string1 == string2)
        printf("shared. 1Addr: %d, 2Addr: %d\n", string1, string2);
    else
        printf("not shared. 1Addr: %d, 2Addr: %d\n", string1, string2);
    string1[0] = 'a'; // 若是 pstr 指针，运算会直接停止；
    if (*string1 == 'a')
        printf("writed. %s\n", string1);
    else
        printf("not writed. %s\n", string1);
    return 0;
}